Punch card type time recorders are in widespread use for tracking working hours of employees. Typically, a time card for each employee is prepared for each pay period such as a week. The employee punches in and out by selecting his card from a rack and placing it in the time recorder which prints (punches) the time and perhaps the day of the week or the date. At the end of the pay period, the cards are collected and the work hours are manually compiled to create totals of regular and overtime hours. A new card is also prepared for each employee for the next pay period.
To avoid the manual compilation of the time data, systems have been introduced which store the in and out times for each employee in memory. Cards are still used to maintain a paper record. For the electronics system to maintain the time record in memory, the employee must identify himself to the electronics as he punches in and out. To that end, information regarding the employee is input to the system along with that employee's number. Employee numbers have been encoded on punch cards in machine readable form. For each pay period, the user purchases a block of punch cards which are sequentially numbered and encoded, the number of cards in a block of cards being at least as great as the number of employees.
Yet another approach has been the use of cards having machine readable magnetic stripes. The employee number and other information is magnetically encoded on the card by the time recorder and is later read by the time recorder each time the employee punches in and out.